Metal salts of phosphorus pentasulfideolefin reaction products



United States Y atent METAL SALTS OF PHOSPHORUS PENTASULFIDE- OLEFiN REACTION PRODUCTS Lyle A. Hamilton, Pitman, Phillip S. Landis, Mickleton, and Francis M. Seger, Pitman, N. J., assignors to Socony Mobil Oil Company, Incorporated, a corporation of New York No Drawing. Application December 30, 1953 Serial No. 401,412

8 Claims. (Cl. 252-325) This invention relates to a new class of phosphorusand sulfur-containing metal salts and to mineral lubricating oil compositions containing the same.

It is well known to those familiar with the art that mineral oil products refined for their various uses are in and of themselves usually deficient in one or more respects so that their practical utility is limited even in the particular field for which they have been refined. For example, mineral oil fractions refined for use as lubricants have a tendency to oxidize under conditions of use with the formation of sludge or acidic oxidation products. These acidic oxidation products exert a corrosive action on the metal parts being lubricated, particularly the metal bearings, such as cadmium-silver alloy bearings, utilized in modern internal combustion engines. In order to prevent the formation of such products and thereby extend the useful life of the oil, it has become the practice to blend with the oil a chemical ingredient which will have the efiect of inhibiting the oxidation of the oil. Such ingredients are known as oxidation inhibitors or anti-oxidants.

It is also well known that lubricating oils when utilized in internal combustion engines tend to form carbonaceous deposits which fill the slots in the oil rings causing the rings to stick and thereby materially reducing the efiiciency of the engine. Chemical ingredients have also been developed which when added to an engine oil have the ability to reduce this tendency of the oil to form deposits which interfere with the function of the piston rings. These addition agents are known as detergents.

In the manufacture of lubricating oil additives particularly anti-oxidants, it is a well known practice to react hydrocarbon materials with phosphorus sulfides to produce acidic, phosphorusand sulfur-containing reaction products which are then neutralized with basic metal salts to produce metal salt additives. Olefinic hydrocarbons of various types have been used in such manufacture. For example, mixed olefin fractions produced by the cracking of petroleum hydrocarbon materials, such as lubricating oils and waxes, have been used for this purpose. Such olefins when reacted withphosphorus pentasulfide, for example, and converted to metal salts provide highly effective anti-oxidants for lubricating oils. These salts, however, are characteristically not satisfactory as detergents. Therefore, in order to provide lubricating oils having good detergent as well as anti-oxidant character, it has been necessary to incorporate therein a separate detergent additive along with an anti-oxidant salt of this type.

We have now found, however, that olefin-phosphorus sulfide product metal salts which exhibit not only high anti-oxidant ability but which are also superior detergents for lubricating oils can be prepared by utilizing in the preparation thereof a novel type of olefinic material, viz., a mixed olefinic fraction having a continuous boiling range between about 500 F. and 1000 F. and which is produced by liquid-phase cracking, at temperatures of from about 700 F. to about 850 F., of a petrolatum "ice 2 filtrate consisting of from about 70 to about weight percent of microcrystalline wax and from about 10% to about 30% of petroleum lubricating oil, such petrolatum filtrate having a specific gravity of between about 0.87 and about 0.88 and not more than about 20 weight percent thereof boiling below about 900 F.

As far as we are aware, the particular olefinic fractions thus produced have not been known heretofore and, accordingly, they are believed to be new compositions of matter. Likewise, metal'salts of the phosphorus pentasulfide reaction products of these olefins are considered to be new and difierent from any analogous salts known heretofore.

We have found thatolefinic fractions derived from the cracking of other petroleum stocks, such as waxes and oils as shown in the prior art, after conversion to equivalent phosphorus pentasulfide metal salts, are definitely inferior as lubricating oil detergents to the metal salts contemplated herein.

It is, therefore, an object of this invention to provide a. new specific class of olefinic materials. It is a further object to provide a new class of metal salts of reaction products of these olefinic materials with phosphorus pentasulfide. It is also an object of this invention to provide oil compositions containing the said metal salts, which compositions exhibit high detergency as well as antioxidant ability. Other and further objects of the invention will be apparent from the following description thereof.

The olefins. contemplated herein. are believed to.- be naphthenic in type, as it has been found that olefins of the straight-chained type derived from the cracking of predominantly straight chain paraffins, such as paraffin wax, provide inferior reaction products. Also, olefins derived from the crackingof lubricating oils of paraffinic or aromatic character are clearly inferior.

The petrolatum filtrate contemplatedby this invention is a non-aromatic material separated in the processing of cerese wax. Two typical petrolatum filtrates utilized herein had the analytical data given in Table I. For purpose. of comparison, similar data for other hydrocarbon stocks employed in the development of this invention are also listed in the table. It will be noted that the petrolatum filtrates had specific gravities of between 0.87 and 0.88, whereas other stocks, all of which proved to be unsatisfactory, where either parafiinic and had a lower gravity or were aromatic and had a higher gravity. Also, the petrolatum filtrates had boiling ranges generally of from 600 F. to 1200 F., not more than 20% thereof boiling below about 900 F. The exact structure or structures present in the petrolatum filtrates which make them suitable for use in this invention are not known,

although, as aforesaid, it is believed from their physical properties that a high naphthene content may account for the enhanced detergency character of the phosphorus pentasulfide metal salt reaction products thereof.

The cracking of the petrolatum filtrate may be carried out in a variety of ways. However, it is preferred to use a liquid-phase operation at temperatures of from about 700 F. to about 800 F. A high yield. of cracked distillate boiling above 500 F. is obtained when the cracking under similar conditions. of other petroleum hy-n drocarbon stocks, viz., (1) Vacwax 40 stock, which is a mixture of paraffin wax and microcrystalline wax, predominantly parat'rin wax, (2) Atlas Cylinder stock, a heavy Mid-Continent lubricating oil vacuum distillate, (3) 345 /2 stock, a solvent-refined paraffin oil and (4) 307 stock, a solvent-refined Mid-Continent lubricating oil. Yet, there is a decided diiference in value as detergents when these olefinic materials are converted first to the phosphorus pentasulfide reaction products and then toir netal salts.

- "The metal salts in all cases were prepared by first reacting the cracked olefin material with from about 5 to'about 30 weight percent of phosphorus pentasulfide, at' a moderately elevated temperature, i. e., from about 140 C; to about 160 C., for a period of from about 1 to about 5 hours, although temperatures as low as 100 C. and longer reaction times up to, say, hours or more mayalso be used. The reaction product'was filtered in all cases to remove any unreacted phosphorus pentasulfide and then hydrolyzed with a small amount, about 5% by weight; of water and neutralized with a basically reacting inorganic metal salt, such as a metal oxide or hydroxide. To illustrate in detail the manner of preparation of the metal salt products contemplated herein, the following specific examples are given. 7

EXAMPLE I' A SOO-gram portion of olefin Cut 6 (run No. Dl0181, Table II) and 100 grams of P 5 were heated with stirring at 150-160 C. for 3 hours. The crude product was filtered with suction through paper giving 580 grams of a viscous oil. To this material in a liter flask there was added 50 grams of zinc oxide and 25 grams of water. The flask contents were heated rapidly with stirring to 150 C. and held there for 2 hours, while 13 ml. of water was collected in a side arm takeoff trap. The reaction product was filtered with suction through paper and gave- 575 grams of a viscous oil. This material contained 3.34% zinc, 4.15% phosphorus and 7.78% sulfur.

EXAMPLE II A 2908.gram portion of olefin bottoms from visbroken petrolatum filtrate (run No. T-850, Table II) and 222 grams ofP 'S were stirred together at 150-160 C. for 4 hours. The resulting solution was filtered free of sludge and unreacted P 8 giving 3090 grams of intermediate reaction product. A l000-gram portion of this reaction product, 500 ml. of toluene and 80 grams of barium hydroxide octahydrate were stirrred together in a 3-liter flask fitted with a stirrer, thermometer and water takeoff trap. -,The flask contents were heated slowly to 130 C., taking off a total of 39' ml. of water after 2 hours at this temperature; The crude reaction product was filteredwith. difliculty and, after'topping free of toluene under vacuum, gave 961 grams of viscous dark-colored material.- This productcontained 2.96% barium, 1.67% phosphorus and 3.27% sulfur.

EXAMPLE In A 3000-gram portion of olefin bottoms from the distillation of cracked petrolatum filtrate (run'No. D10474, Table II) and 580 grams of P 8 were stirred together at 145148 C. for 3 hours in a l0-liter flask under nitrogen. The product was cooled to C. and 150 ml. of water added dropwise in the course of one hour. The temperature was then raised to 150 C. taking off unreacted water in a takeoff device and held at this temperature for 3 hours. The product was filtered hot through Hyfio (a diatomaceous earth filter aid) using suction. To a l775-gram portion of this intermediate there was added 81 grams of'zinc oxide and the reactants stirred at 150 C. for'3 hours. The product was filtered 4 with difliculty through Hyflo, giving 1801 grams of product. This product contained 3.10% zinc, 4.29% phosphorus and 4.97% sulfur.

A number of other metal salt products, all prepared in a manner similar to that shown in the foregoing examples, are listed in Table III.

Evaluation of products The evaluation of the products of this invention, as detergents as well as inhibitors of bearing corrosion, was carried out by means of the Lauson D4A engine test. This test rates piston cleanliness as well as bearing corrosion. The engine is inspected for cleanliness of the rings, ring grooves and piston skirt. Cleanliness ratings are made, based on a scale of from to 0, a rating of 100 signifying a perfectly clean engine and a rating of 0 representing the worst possible deposit condition. The engine is perfectly clean at the start of each test and the copper-lead bearing of the engine is accurately weighed before and after the test run and the loss in weight thereof is recorded. The test involves operation of the single cylinder, 4-cycle, liquid-cooled gasoline engine for 100 hours under the following conditions:

Oil temperature F 270 Jacket temperature *F-- 212 Speed R. P. M.-- 1825 /2 throttle I 13.0-1 air-fuel ratio Oil added every 20 hours cracking a number of other hydrocarbon oils and waxes.

The base oil used in all of the test blends was an S. A. E. 20 grade, solvent-refined Pennsylvania oil having a kinematic viscosity of 63 centistokes at 100 It will be seen that the oil blends of the products contemplated herein gave consistently good detergency (cleanliness) ratings, i. e., from 73 upwards to as high as 85, while that of all the other products were relatively poor. It is believed that these data clearly demonstrate that the metal salt products produced from the cracked petrolatum filtrate (microcrystalline Wax-oil mixture) as herein contemplated, provide unexpectedly high detergeney activity in lubricating oils over the metal salt products prepared from other olefinic stocks. As has been stated hereinbefore, the cracking of the petrolatum filtrate may be carried out in any suitable manner to give olefinic fractions satisfactory for use in this invention. sistently best results are obtained by the use of thermal, liquid-phase cracking under either atmospheric or reduced pressures as low as about 50 mm. (absolute pressure) or lower, at temperatures of about 700 F. to about 850F., the lower temperatures within this range being preferred where lowered pressures are employed. Also, itris preferable to use the highest boiling olefinic fractions, i. e.,, those having continuous boiling ranges above about 500 'F.Iand preferably Within the limits of from about 500 F. toiabout 1000 F., in order to provide oil solubility'in the reaction products. However, the use of small amounts, i. e., from about10% to about 20%, of olefins having a 400 F. to 500; F boiling range along with higher boiling olefins will provide highly satisfactory products. i V The metal salts contemplated herein are those of the However, we have found that the con- .6 metals ofGroup II of theMendeleefi Periodic Table, par: about dependingupon. the particular oil to ,be im' ticnlarly the'salts of barium, calcium, magnesium, st'ronproved and'the application for which it-is intended;

tium and zinc, with the barium salts being especially It is also contemplated that other additives designed preferred; to improve the oil in various-respects, such-as pour de- Th'e amount of metal saltreactant productto 'be utilized 5 pressants, viscosity improvers, extreme pressure agents, in the oil will range generally from about-0.5% to about etc., may also be used in the oil along with the additives 'by weight and usually will be from about 1% to herein contemplated.

TABLE I.CHARGE STOCKS FOR LIQUID-PHASE CRACKING Petrolatum Petrolatum Vacwax 345% P. D. 345%,

Identification Filtrate Filtrate Raffinate Furiural 307 Stock A B Rafiinato Specific Gravity. 0.8772 0.8772 0.84 0. 9303 0. 8916; 08911 i Viscosity, cs. 210 F 25. 85 20. 58 6. 58 30.84 18. 97 17. Vacuum Assay: IBP F.) 720 620 l 10 955 860 5 915 l 960 I 1, 005 l 1, 050 1,100 l 1,140.

95-- Molecular Weight 660 Bromine Number l. 1 3. 6 Olefin Content, Percent 5 l5 TABLE II:OLEFINIC FRACTIONS FROM CRACKED STOCKS Liquid Olefin Cracking Charge Fraction Utilized Recovery, Distillation Specific Br. Moi. Content,

' Range, F. Gravity No. Wt. Percent- Percent T850, Bottoms 90 510-1, 100 0. 8660 11. 2 570 40 D3902, Bottoms 35 700 0. 8866 21. 5 600 84 D211, Bottoms. 78 700 Petrolatum Filtrate D10181, Cut 5 12 517-604 08270 46. 4 242 Cut 6 19 602-686 0. 8358 32; 9 308- 63 Bottoms 48 672-894 0. 8565 17. 6 400 44 D10474, Bottoms- 78 519-953 0.8607 26. 1 380 62 D10178, Cut 4-- 18 396-498 0. 7870 48. 3 190. 57 Vacwax'40 Cut 5 21 515-590 0. 8008 34. 6 238 51 26 565-751 0. 8165 15. 2 300 29 3452/ Stock Propane Deasphalting 47 0.9478 23. 6 440 65 345% Stock Furfural Raifmate 49 0.8950 17. 5 470 51 307 StockPropaue Deasphaiting Rafiinate. 12 615-782 0. 8927 23. 2 325 47 Atlas Cylinder Stock 34 630-840 0. 8973 24. 6 330 51 l Allcracking-runs except T850 and. D3902 were by batch liquid-phase operation at 700750 F. The T850 run was made by cracking in a coil under vis-breaking conditions. Run D3902 was vapor-phase cracking at 1050 F.

TABLE III.ADDIT I [VES PREPARED FROM CRACKED STOCKS Cracking Product Additive Preparation and Analyses Lauson D-4-A Evaluation I P, S, Percent Percent Oleanli- 1g Brg. Source Fraction Metal, Percent Per Per- Additive Metal in ness Wt.

1 cent cent in {)Ijest Test Oil Rating Loss, g.

None 52 l Petrolatum-Filtrete '13-850, Bottoms None 1. 7 3. 6 5; 9 57' 5 34516, Stock Propane Deasphalting Bottoms Barium, 5.3 3. 8 63 Rafllnate. F 307 Stock Propane Deasphalting D-209, Bottoms Barium, 1.45.-.. 1. 81 3.86 13. 8 0.2 Ba.. 47 Raflinate. Atlas Cylinder Stock D-213, Bottoms Sodium, 1.06.... 0.87 1.85 2. 9 0.034 Na 62 va wa'x io 1335101158, Cuts 4, 5 and Zinc, 2.9.----.... 4. 86 7. 47 2. 0 0.058 Z11.-... 61

o oms. Petrolatum Filtrate T-850, Bottoms Barium, 2.96.-.. 1.67 3. 27 3. 4 0.1 Ba 35 D do Barium, 1.69.... 1.67 3. 56 go 2% a T-850, Bottoms 1 Banum, 2.64.--- 1. 44 2. 92 6 023a. 77

Barium, 5.62. 3. 6 0.2-Ba.. 79 Barium, 1. 73 2. 94 4. 8 0.2 Ba 73 Barium, 3.0 1. 89 3. 57 6. 7 0.2 Ba 75 Calcium, 1.42. 2.05 3.09 4; 1 0.058 Ca 74' Barium, 5 1 1.94 4. 06 3. 9 0.2 Ba.....-. 73 Barium, 1 8. 1. 48 3.04 11. 1 0.2 Ba 73' Barium, 3 6 1. 81 3. 54 5.6 0.2 Ba..- 70 Zinc, 2 1.- 4. 5 0.095 Zn 78 Zinc, 3.34. 4 15 7. 78 2. 0 0.068 Zn 80' Zinc, 2.82. 2. 0 0.056 Zn.. 75 Barium, 3.7. 4.19 3. 99 2.0 0.08 Ba 73 Barium, 3.4.. 5. 9 0.2 Ba 73" Y Zinc, 2.87......- 4. 16 5. 40 2. 0 0.058 Zn 80 0.007 :22 as 58 72 n.-..- 75 0.007; 13-10474- 30mm 4.06 5. 4o 4. 0 0.113 Zn s1 0.00s 4. 06 5. 4O 8. 0 0236211-... 81 0'. 010 do' Zinc, 3.10 4. 29 4. 97 2.0 0.060 Zn-.... 85 0. 007

- 1. Percolation oi olefinicxnaterial before PzSs' reaction reduced color and specific gravity with slight reduction in bromine number. 4 0.2% bgrinm equivalent to 0.095% zinc; 0.068% calcium; 0.057% sodium. V

Having nowyfully described the invention, what is claimed as new and-patentable is; I a -1'." As a new composition of matter, a metal-, phosphorusand sulfurcontaining product produced by the steps'of (1 reacting (A) an olefinic hydrocarbon material having a continuous boiling range of from about 500 F. to about 1000 F., produced by the liquid-phase thermal cracki-ng'at a temperature of from about 700 F. to about 850 F., ofa petrolatum filtrate characterized as follows: (a) consisting of from about 70 to about 90 weight percent of microcrystalline wax and the remainder 'lubr'icating'oil, (b) having a specific gravity of from about 0.87 to about 0.88and (c) not more than 20% thereof boiling below about 900 F. with (B) from about 5 to about 30'.weight percent of phosphorus pentasulfide at a temperature of from about 100 C. to about 160 C. to 1 rial having a continuous. boiling range or" from about 500 F. to about 1000 F., produced by the liquid-phase thermal cracking at a temperature of from about 700 F.

to about 850 F., of a petrolatum filtrate characterized as follows: ([1) consisting of from about 70 to about 90 weight percent of microcrystallinc wax and the remainder lubricating oil, (b) having a specific gravity of from about 0.87 to about 0.88 and (c) not more than thereof boiling below about 900 F, with (B) from about 5 to about weight percent of phosphorus pentasulfide at a temperature of from about 100 C. to about 160C. to form an acidic, phosphorusand sulfur-containing product and (2) reacting the product'of step 1 with barium.

hydroxide to form a barium salt thereof.

3. As a new composition of matter, a metal-, phosphorusand sulfur-containing product produced by the steps of (1) reacting (A) an olefinic hydrocarbon material having a continuous boiling range of from about 500 F. to about 1000 F., produced by the liquid-phase thermal cracking at a temperature of from about 700 F. to about 850 F., of a petrolatum filtrate characterized as follows: (a) consisting of from about 70 to about 90 weight percent of microcrystalline wax and the remainder lubricating oil, (b) having a specific gravity offrom about 0.87 to about 0.88 and (c) not more than 20% thereof boiling belowabout 900 F. with (B) from'about 5 to about 30 weight percent of phosphorus pentasulfide at a temperature of from about 100 C. to about 160 C. to form an acidic, phosphorus and sulfur-containing product and (2) reacting the product of step 1 with calcium hydroxide to form a calcium salt thereof.

4. As a new composition of matter, a metal-, phosphorusand sulfur-containing product produced by the steps of (l) reacting (A) an olefinic hydro-carbon material having a continuous boiling range of from about 500 F. to about 1000 F., produced by the liquid-phase i at a temperature of from about 100 C. to about 160 C.

to form an acidic, phosphorusand sulfur-containing product. and (2) reacting the product of step 1 with zinc hydroxide to form a zinc salt thereof.

" 5. A mineral lubricating oil containing from about 0.5

1000 F., produced by'the liqui d-phase thermalcracking at atemperature of from about 700 F. to about 850 F;, of a petrolatum filtrate characterized as follows: (a) consisting of-from about 70 to about 90 weight. percent of microcrystalline wax and the remainder lubricating-oil, ([7) having a specific gravity of from about 0.87 to about 0.88 and (c) not more than 20% thereof boiling below about 900 F. with (B) from about 5 to about 30 weight percent of phosphorus pentasulfide at a temperature of from about 100 C. to about 160 C. to form an acidic, phosphorusand sulfur-containing product and 2) react ing the product of step 1 with a basically reacting metal salt of 'a metal selectedfrom group II of the periodic table, to form-ametal salt thereof.

6. A mineral-lubricating oil containing from about 0.5 to about 10 percent by weight of a metal-, phosphorusand sulfur-containing product produced by the steps of I (1) reacting (A) an olefinic hydrocarbon material having a continuous boiling range of from about 500 F. to about 1000 F., produced by the liquid-phase thermal cracking at a temperature of from about 700 F. to about 850 F., of a petrolatum filtrate characterized as follows: (a) consisting of from about 70 to about 90 weight percent of microcrystalline wax and the remainder lubricating on, (b) having a specific gravity of from about 0.87 'to about 0.88 and (c) not more than 20% thereof boiling below about 900 F. with (B) from about 5 to about 30 :weight percent of-phosphorus pentasulfide at a temperature of from about 100 C. to about 160 C. to form an .acidic,.phorphorusand sulfurrcontaining product and (2) reacting the product of step 1 with barium hydroxide to form a barium salt thereof.

7. A mineral lubricating oil containing from about 0.5 to about 10 percent by weight of a metal-, phosphorusand sulfur-containing product produced by the steps of (l) reacting (A) an olefinic hydrocarbon material having a continuous boiling range of from about 500 F. to

' '(a) consisting of from about 70 to about 90 weight percent of microcrystalline wax and the remanider lubricating oil, (b) having a specific gravity of from about 0.87

to about 0.88 and (c) not more than 20% thereof boiling below about 900 F. with (B) from about 5. to about 30 weight percent of phosphorus pentasulfide at a temperature of from about .100 C. to. about 1.60 Cato form.

an acidic, phosphorusand sulfur-containing product and 2) reacting the product of step 1 with calcium hydroxide to form a calcium salt thereof.

8. A mineral lubricating oil containing from about 0.5

to about 10 percent by weight of a metal-, phosphorusand sulfur-containing product produced by the steps of (1) reacting (A) an olefinic hydrocarbon material having a continuous boiling range of from about 500 F. to about 1000 F., produced by the liquid-phase thermal cracking at a temperature of from-about 700 F. to about 850 F.," of a petrolatum filtrate characterized as follows: (a)

oil, (b) having aspecific gravity of from about 0.87 to about 0.88 and (c) not more than 20% thereof boiling to about 10 percent by weight of a metal-, phosphorusand sulfur-containing product produced by the steps of 1) reacting (A) an olefinic hydrocarbon material having a oontinuous boiling range of from about 5 00 F. to about below about 900-F.- with (B) from about 5 to about 30 weight percent. of phosphorus pentasulfide at a temperature of from about C. to'about C. to form an acidic, phosphorusand sulfur-containing product and (2) reacting the product of step 1 with zinc hydroxide to form a zinc salt thereof. 7 f

References'Cited in the file of this patent 

5. A MINERAL LUBRICATING OIL CONTAINING FROM ABOUT 0.5 TO ABOUT 10 PERCENT BY WEIGHT OF A METAL-, PHOSPHORUSAND SULFUR-CONTAINING PRODUCT PRODUCED BY THE STEPS OF (1) REACTING (A) AN OLEFINIC HYDROCARBON MATERIAL HAVING 1000* F., PRODUCED BY TEH LIQUID-PHASE THERMAL CRACKING AT A TEMPERATURE OF FROM 700* F. TO ABOUT 853* F., OF A PETROLEUM FILTRATE CHARACTERIZED AS FOLLOWS: (A) CONSISTING OF FROM ABOUT 70 TO ABOUT 90 WEIGHT PRECENT OF MICROCRYSTALLINE WAX AND THE REMAINDER LUBRICATING OIL, (B) HAVING A SPECIFIC GRAVITY OF FROM ABOUT 0.87 TO ABOUT 0.88 AND (C) NOT MORE THAN 20% THEREOF BOILING BELOW ABOUT 900* F. WITH (B) FROM ABOUT 5 TO ABOUT 30 WEIGHT PERCENT OF PHOSPHORUS PENTASULFIDE AT A TEMPERATURE OF FROM ABOUT 100* C. TO ABOUT 160* C. TO FORM AN ACIDIC, PHOSPHORUX- AND SULFUR-CONTAINING PRODUCT AND (2) REACTING THE PRODUCT OF STEP 1 WITH A BASICALLY REACTING METAL SALT OF A METAL SELECTED FROM GROUP II OF THE PERIODIC TABLE, TO FORM A METAL THEREOF. 